Why are forests important to climate change?

Forests play a critical role in regulating the global climate. They store vast amounts of carbon and also continue to absorb it from the atmosphere.

The world’s forests are thought to hold around 861 billion tonnes of carbon. For comparison annual global emissions from fossil fuels are around 37 billion tonnes of greenhouse gases.

In the UK forests hold around 3.7 billion tonnes of carbon, equivalent to ten years of the UK’s entire emissions.

Forests also play an extremely important role as a home to wildlife, in cleaning air and water, and providing livelihoods for people.

Forests are found all over the world but more than half of them are found in just five countries: Brazil, Russia, Canada, the US and China, though the forests in Australia and the Democratic Republic of Congo are also significant.

Forests cover 4 billion hectares of land, or 38% of the world’s surface. Russia is home to 20% of the world's forests, followed by Brazil with 12%, Canada with 8.5%, the US with 7.6%, and China with 5.4%.

Just under a quarter of the world’s forests are ‘primary’ (meaning they have never been logged) and over half have naturally regenerated; the remainder is planted forest.

Since the last Ice Age one third of the world’s forests have been lost, with half of that loss occurring only in the last century. The world loses around 5 million hectares of forests every year – that's equivalent to more than twice the size of Wales – with 95% of this loss occurring in tropical countries.

• Agriculture: Three quarters of the loss of forests is to make way for agriculture. Over half of all deforestation is to graze cattle and to grow oilseeds - soya and palm oil - that are used to feed livestock, as ingredients in food and cosmetics, or as a form of transport fuel. Half of all tropical deforestation is in just two countries: Brazil and Indonesia.
• Climate Change: Climate change is itself exacerbating the loss of forests through wildfires.

• Other Human Activity: There are also other human threats to forests. Deliberate fires are used as a cheap way to clear land, but can often get out of control and turn into much bigger fires. Drainage of swamp forests can lower their water table and make them far more vulnerable to fire and make trees more vulnerable to high winds as soils dry out. Development (roads, rail, canals) and logging to harvest timber or make way for mining or agricultural land, all impact forests. This can also impact on indigenous peoples who make up just 4% of the world’s population but care for 80% of the world’s nature, much of it in forests.

There are many efforts to protect and restore forests, with varying degrees of success. One of the most notable examples is Costa Rica a country which was 75% forest in the 1940s. Logging resulted in half the country’s forests being lost by 1990. But strong enforcement policies, restrictions on the number of logging permits, and payments for local communities caring for and restoring forests worked: 60% of the country is now forested again.

Meanwhile Brazil has moved in the opposite direction. In the first decade of this century it made huge efforts to reduce deforestation and, as a result, its greenhouse gas emissions also fell. But since the election of President Jair Bolsonaro that progress has been undone with deforestation soaring to record levels in recent years.

This year the LEAF Coalition was launched between governments and private companies, aiming to generate $1 billion of public and private money to protect tropical forests. As part of its presidency of COP26 the UK Government has been working with Indonesia on a series of dialogues between countries that produce and countries that buy the products that are causing deforestation (such as beef or soy) with the aim of finding ways to end the deforestation impact of this trade.

Around 13% of the UK’s land is covered by forests. This level of cover is far lower than other European countries which average around 37%. The Government, following advice from the Climate Change Committee, is aiming for the UK to plant 30,000 hectares of trees per year from 2025 onwards. In its Net Zero Strategy it says this will mean tripling tree planting rates in England, which are currently around 2000 hectares per year, to 6000 hectares per year.

This will mean creating an area around twice the size of Cardiff every year through planting or through allowing trees to return to areas naturally. This means that by 2050 the UK will have somewhere between 17-19% tree cover (compared to 13% today).

Better management of the UK’s existing forests and woodlands, and expansion of them, will be crucial to restoring nature and helping to protect declining species of wildlife, as well as reducing our carbon emissions.